Re: [Tutor] How to calculate pi with another formula?
On 4/14/05, Kent Johnson <[EMAIL PROTECTED]> wrote: > Dick Moores wrote: > > Now to my new question. I have an artist friend who knows an artist who > > needs pi expressed in base 12. I don't know how many digits he needs, > > but I think he'll take what he can get. Is there a way to use > > math.log(x, base) with the decimal module to accomplish this? Or is > > there another way? Or is there no way? > > I think I would try to write a program that converts base-10 decimal > fractions to base 12. Then feed > it the output of a pi-generating program. > I just thought I would reference the fascinating thread that ensued from this request on comp.lang.python : http://groups-beta.google.com/group/comp.lang.python/browse_frm/thread/1839b7d733ae37d0/3b5f7138f0e5fbd1?q=pi+base+12&rnum=1#3b5f7138f0e5fbd1 Peace Bill Mill bill.mill at gmail.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How to calculate pi with another formula?
Dick Moores wrote: Now to my new question. I have an artist friend who knows an artist who needs pi expressed in base 12. I don't know how many digits he needs, but I think he'll take what he can get. Is there a way to use math.log(x, base) with the decimal module to accomplish this? Or is there another way? Or is there no way? I think I would try to write a program that converts base-10 decimal fractions to base 12. Then feed it the output of a pi-generating program. Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How to calculate pi with another formula?
Gregor Lingl wrote at 11:27 10/29/2004: Hi Dick! Accidentally I just was tinkering around with the new decimal module of Python2.4. (By the way: it also works with Python 2.3 - just copy it into /Python23/Lib) The attached program uses a very elementary (and inefficient) formula to calculate pi, namely as the area of a 6*2**n-sided polygon (starting with n=0), inscribed into a circle of radius 1. (Going back to Archimedes, if I'm right ...) Nevertheless it calculates pi with a precision of (nearly) 100 digits, and the precision can be arbitrarily enlarged. In the output of this program only the last digit is not correct. import decimal decimal.getcontext().prec = 100 def calcpi(): s = decimal.Decimal(1) h = decimal.Decimal(3).sqrt()/2 n = 6 for i in range(170): A = n*h*s/2 # A ... area of polygon print i,":",A s2 = ((1-h)**2+s**2/4) s = s2.sqrt() h = (1-s2/4).sqrt() n = 2*n calcpi() Just for fun ... Gregor This works great, and if I change the precision to, say, 2000, and the range to 2000, I get pi accurate to the 1,205th digit (this took 66 minutes, with psyco employed), when I compare with the pi pages on the web. Now to my new question. I have an artist friend who knows an artist who needs pi expressed in base 12. I don't know how many digits he needs, but I think he'll take what he can get. Is there a way to use math.log(x, base) with the decimal module to accomplish this? Or is there another way? Or is there no way? Thanks, Dick Moores [EMAIL PROTECTED] ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
